1. Field of the Invention
The present invention relates to a junction between superconducting wires which are prepared from oxide high-temperature superconductive materials.
2. Description of the Background Art
In recent years, superconductive materials of ceramics, i.e., oxide superconductors, are watched with interest as those which can exhibit higher critical temperatures. Among such materials, particularly expected for practical application are yttrium, bismuth and thallium based superconductors, which exhibit high critical temperatures of about 90 K, 110 K and 120 K respectively. Such high-temperature superconductive materials may be applied to a cable, a bus bar, a current lead, a coil and the like, and technique for elongation of superconducting wires has been developed.
In application of such high-temperature superconductive materials, it is necessary to obtain long wires having stable properties, as well as to form a junction, which is stabilized and brought into a superconducting state, between such superconducting wires in a state capable of ensuring a heavy current. In particular, a permanent current junction is required in application to a coil. In such a permanent current junction, it is necessary to join superconductors to each other in order to carry a superconducting current.